In bone-chilling cold and wintry darkness, US Forest Service snow rangers and a platoon of volunteers spent hours rescuing three hikers who slid some 800 feet during an avalanche while climbing Huntington Ravine in New Hampshire’s White Mountain Forest, officials said today.

A total of 12 people were making their way through the ravine roped together into groups of three hoping to summit to Mount Washington Thursday afternoon when the avalanche occurred, according to a forest service spokeswoman and facebook postings.

The avalanche swept one group of three some 800 feet, a group that included former US Marine Sergeant Keith Zeier, who lost a leg while serving in Iraq. Zeier and the 11 other people are part of Ascents of Honor, a non-profit organization raising money for special operations veterans like Zeier who were injured during their service.

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In their posting today on Facebook, the organization described the incident.

“As we approached the top of Huntington Ravine, a slab avalanche broke loose and swept three of our climbers down to the bottom of the ravine,’’ the posting read. “They were injured, but able to slowly make their way to rescuers, who assisted them off the mountain.’’

Zeier and two other hikers were taken to Androscoggin Valley Hospital in Berlin. A hospital spokesman said today he could not provide any information about the condition of Zeier and the others.

The remaining nine hikers walked out on their own power, the posting notes.

“While this is certainly not the outcome we had hoped for, we are thankful that all in our party are safely off the mountain. We extend a heartfelt thanks to the US Forest Service and local Mountain Rescue Service personnel for their assistance, and look forward to sharing more details after we all get some rest,’’ the posting notes.

Stephanie White was one of the climbers who did not slide all the way down.

“I heard someone yell ‘Avalanche!’” she said in a telephone interview. “Next thing I know I was hit by a wall of snow. I lost grip of my tools and got launched backward.”

“The whole thing going through my head was ‘Huh, this could be it,’” she said. “And then I thought, ‘No, it can’t be it.’ It wasn’t noisy, it was actually fairly calming. I was just trying to swim and keep the snow off my face.”

White said she continued to push the snow to her face until she felt a jerk to her climbing harness and was pulled up and out of the main slide by the other two members of her three-person rope team.

According to Tiffany Benna, spokeswoman for the White Mountain National Forest, forest service snow rangers learned of the avalanche and injuries around 5:30 p.m. Thursday. With the support of the 19 volunteer rescuers, most from the North Conway Mountain Rescue Service, the three injured people were loaded onto litters.

The injured were then loaded onto a snowcat and driven down to Pinkham Notch parking lot where ambulances from the Gorham Emergency Medical Services and the Bartlett-Jackson ambulance service were waiting.

Chad Miller, director of Gorham’s EMS, said the hikers arrived in the lot around 8:30 p.m., and that the three male patients were at the Berlin hospital about 30 minutes later. He said the patients asked his department not to discuss their injuries.

Miller said the temperatures were 10 below zero with a strong gusting wind during the rescue.

He noted that Mount Washington is considered one of the most dangerous to hike.

“It really is a whole another world up there,’’ he said.

Globe correspondent Derek Anderson contributed to this report. John R. Ellement can be reached at ellement@globe.com.